Automatic choke for carburetors



June 23, 1931. JQECK 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS Filed Dec. 14, 1928 4 Sheets-Sheet 1INVENTOR flomtfoeck,

ATTOR N EY June 23, 1931. DJJOECKY 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS Filed Dec. 14, 1928 4 Sheets-Sheet 2INVENTOR flaw/5,3 uzl' 2 7 7 ATTORNEY June 23, 1931. T. D. JOECK1,811,354

AUTOMATIC CHOKE FOR CARBURETORS Filed Dec. 14, 1928 4 Sheets-Sheet sl/ll/ I I l 26 1 30 llllllll/IIIIIIIII INVENTOR fla r n53 fiec';

@ 92. ATTORNEY June 23, 1931. T. D. JOECK 1,811,354

AUTOMATIC CHOKE FOR CARBURETORS v Filed Dec. 14, 1928 4 Sheets-Sheet 4ATTORNEY Patented an. 23, 1931 STATES PATENT}; OFFICE THOMAS D. JOECK,0F IBELMAIR, NEW JERSEY AUTOMATIC CI EI IOKE FOR CARBURETORS Applicationfiled December 14, 1928. swarm. 325,992.

ing period; and the invention has reference, I

more particularly, to a construction of automatic choke forcarburetorsof internal com-' bustion engines.

One object of the invention is to provide a choke of the above characterthat automatically varies the supply of air to the internal com-wbustion engine carburetor in accordance with therequirenientsof theengine. tr Another object of the invention lies in the provision of achoke of the above character "that controls the supply of air so thatthe mixture ofv fuel and air is such as to enable the engine to operateat the maximum of econ- 20 omy.

Still another object of the invention is to provide a choke of the abovecharacter that is of simple, strong construction and which is reliablein operation. o

Other objects of this invention, not at this time more particularlyenumerated will be clearly understood from the following detaileddescription of the same.

. V The invention is clearly illustrated in the accompanying drawings;in which Fig. l is a view in side elevation with parts broken'away of aninternal combustion engine carburetor equipped *with the novel automaticchoke of this invention;

Fig. 2 is a sectional View taken along line 2-2'ofFig1; T

Fig. 3 is an enlarged vertical sectional view of the automatic chokeillustrated in Fig. 1, the valve of said choke being illustrated in itsclosed position; 1 i

Fig. 4 is a view similar to Fig. 3 but is taken at right angles theretoand with the choke valve shown in partly open position;

Fig. 5 is a sectional view taken along line 5 of Fig. 4 looking in thedirectionof the arrows;

Fig. 6 is a sectional view taken along line 6-6 of Fig. 4; d

Fig. 7 is a view similar to Fig. 1 but illustrates amodified form ofcontrol;

Fig. 8 is a fragmentary view illustrating one step in the operation ofthe automatic choke; and V Fig. 9 is an enlarged sectional view oi aportion of the structure shown in Fig. 7.

Similar characters of reference are employed in all of the hereinabovedescribed views, to indicate corresponding parts.

Referring now to said drawings, the reference character 1 designates aninternal co1nbustion engine having a carburetor 2 equipped with thenovel automatic choke of this invention. This automatic choke comprisesa choke valve casin 3 having a cone shaped air discharge nipp e 4, theouter reduced end ofwhich is truncated and is adaptedto be positionedwithin the inlet opening of the carburetor air intake pipe 5. Valvecasing 3 is illustrated as being of substantially rectangularcross-section and as being made up of a pluralit of plates securedtogether as by rivets. two flat side plates 6 and 7 riveted to theflange of-channel shaped front and rear plates 8 and 9. The ends of thecasing 3 are closed by top and bottom plates 11 and 12, respecs tively.To and bottom plates 11 and 12 are secured to t e remainder of thecasing by ver tically extending spacer rivets 10. Valve casing 3 isretained in desired position With re spect to the intake pipe 5 andissupported from this intake pipe by means of a pair of spaced bolts 13that extend through apertures in the side plate? and in flanges of thefront and rear plates 8 and 9 and also through apertures in a clamp 15secured upon the in- 7 take pipe 5. Clamp 15 comprises upper and lowersubstantially V-shaped separable portions surrounding the intake pipe 5,which portions are retained" in clamping relation upon this pipe bybolts 14', as especially shown in Fig. 2. The bolts 13 by reason oftheir tension act to rigidly retain the reduced end portion of thenipple 4 within and in abutting relation to the end of the intakepipefi, thereby preventing leakage of air between these members. 1

The valve casing 3 is provided with a circular air inlet opening 16extending through the bottom plate 12. The inner marginal ese platescomprise 1 edge portion of the bottom plate 12 surrounding the inletopening 16 provides a valve seat 17 for a choke valve 18. Choke valve 18is secured as by a pin 20 to a vertically extending plunger rod 21. Thevalve seat 17 is surrounded by an annular upwardly and outwardly flaredairbaflie 22. Air baflle 22 is attached in fixed position upon thebottom plate 12 by means of oppositely arranged clips 23 (Fig. 8) thatare soldered or otherwise secured to the outer surface of the bafiie andare'also riveted by spacer rivets 24 to the bottom plate. Spacer rivets24 extend downwardly from the bottom plate and carry a cross-plate 25 attheir lower ends. Crossplate 25 is centrally apertured to receive andsupport a dash-pot 26 extending downwardly from this cross-plate. Ascrew cap 27 is threadedv upon the upper open end of the dash-pot 26 andabuts the upper surface of the cross-plate 25, causing the lowersurfaceof this plate to abut an annular shoulder formed on the dash-pot 26,thereby effecting a rigid connection between the cross-plate anddash-pot.

The lower portion of plunger rod 21 extends through a central aperturein the screw-cap 27 and has a loose fitting check piston 28 threadedupon its lower end. Check piston 28 is provided with a plurality ofapertures 30 extending therethrough, which apertures are normally closedby a relief valve 31 that is slidably mounted upon a sleeve 32surrounding the plunger 21. A washer 33 is supported upon the top ofsleeve 32 and carries a compression spring 34 that bears at its upperend against a washer 35 and tends to urge thecheck piston clownwa'rdlyand also'actsto check the upward movement of the check piston '28 asthis piston approaches the top of the dash-pot. The dash-pot 26 isfilled with a suitable liquid such ,as lubricating oil and a felt washer36 is positioned between screw-cap 27 and washer 35 for retaining thisliquid within-- the dash-pot.

A piston 37 having a piston ring 38 is formed upon the upper end of theplunger rod 21. Piston 37 is adapted to reciprocate within a pneumaticcylinder 40 that has its lower open end portion extending through anaperture in the top platell. A nut 41 is threaded upon the cylinder 40and abuts the lower side of the top plate 11 causing the upper sideofthis plate to abut an annular shoulder formed on pneumatic cylinder 40,thereby rigidly securing this cylinder to the top plate. A cylinder head42 is threaded upon the upper end of cylinder 40. Cylinder head 42 has aport 43 extending from the interior of the pneumatic cylinder through anipple 44 to a'pipe or tube 45 that is connected to the intake manifold46 of the internal combustion engine 1. A felt lubrieating washer 47 ismounted upon the plunger rod 21 adjacent the piston 37: Washer 47isadapted to supply suitable lubricant to the inner walls of cylinder40.

The front plate 8 of valve casing 3 is provided with a substantiallysquare opening or window 49 that is adapted to be closed by a gate valve50. Gate valve 50 is provided with a rectangular aperture 51throughwhich acatch 52 is adapted to Extend. Catch 52 has substantiallythe shape of a sector and is provided with a pair of spaced recesses 53and 54 in its upper arcuate edge. The outer portion of this arcuate edgeis knurled at 55 and the inner portion is extended to form acatch-finger 56. Catch 52 is fixedly mounted, at substantially thegeometrical axis of its arcuate edge, upon the free end of a coil spring57. Coil spring 57 is wound around a pin 58 protruding from the gatevalve and has its other end fixed to the gate valve as by'extendingthrough an aperture therein. Spring 57 urges the catch 52 upwardly andnormally holds either recess 53 or recess 54 in cooperating engagementwith the upper wall of aperture 51 as especially .shown in Fig. 4.

By suitably pressing down as with the thumb upon the knurled portion 55,the

catch 52 may be turned so as to cause either recess 53 or recess 54 toengage the upper 'wall of aperture 51 as desired. With, the

gatevalve 50 closed as illustrated in Fig. 4, when recess 54 engages theupper wall of aperture 51, the catch finger 56 projects into thevertical path of movement of the choke valve 18 at a'certain heightabove the air inlet opening 16, and when the catch 52 is moved so thatthe recess 53 engages the up per wallet aperture 51 then this catchfinger is out of the path of movement of the choke valve and ispositioned as shown by dotted lines in Fig. 4. p

The gate valve 50 is hingedl a pin 60 supported at its ends by theflanges of the front plate 8. An operating pin or lever .61 is securedat its inner end to the gate valve 50 and has its outer end connected toa link 62. Upward movement of link 62 causes gate valve 50 to turn aboutits hinge pin 60 opening the window 49 and permitting air to enter thevalve casing through this window. Movement of link 62 is obtained in thestructure shown in Fig. 1 by connectingthe upper end of this link to acrank 63 which in turn is connected to a suitable push-pull handlemounted on the dash by a link' 64. In the form of the invention shown inFig. 7, link 62 is connected to one arm of a bell crank lever 65 that isfulcrumed upon a thermostatic bellows casing 66. The other arm of thebell crank lever 65 engages the bottom of a recess 67 formed in theouter end of a plunger 68. Plunger 68 extends inwardly of the casing 66and has a disk shaped inner end retained in engagement with athermostatic bellows 70 by. a compression mounted on spring 71. Two suchthermostatic bellows 70 are illustrated as arranged in series in thecasing 66 but it is obvious that. any number of these bellows may beemployed as desired. These thermostatic bellows contain a suitablevolatile liquid and are adapted to expand upon the heating of engineland effect through movementof bell crank lever and link 62 the openingof the gate valve 50.

In operation, when the engine 1 is dead, the choke valve 18 is inengagement with its valve seat 17,.thereby closing the air inlet opening'16 of the choke valve casing 3. As soon as the engine 1 starts to turnover, however the suction developed in the intake manifold 46 creates aregion of reduced air pressure within the choke valve casing 3 and abovethe closed choke valve 18, and also in the pneumatic cylinder 40 abovethe piston 37. Choke valve 18 and piston 37 thereupon move upwardlyowing to the action of the unbalanced air pressure on their undersurfaces. As these members commence to move upwardly, the plunger rod 21moves upwardlytogether with check piston 28. The relief valve 31 acts toclose the apertures 30 of the check piston 28 during this upwardmovement, making it necessary for the liquid in dash-pot 26 in. order topass the loose fitting check piston, to flow between this piston and thewalls of the dash-pot, thereby causing the plunger rod to have 'arelative slow upward movement. This results in a gradual upward movementof choke valve 18 away from its seat 17 cansing a gradual increase inthe volume of air supplied through choke valve casing 3 to thecarburetor by way of intake pipe 5. .This is desirable as it prevents ato rapid inflow of air just at the starting of the engine which wouldtend to stall the same owing tothe presence of too lean a mixture. Justas the choke valve leaves its seat, the relatively small volume of airadmitted results in an extremely rich mixture supplied the engine whichis desired in starting. The bafie 22 coperates with the choke valve 18in restricting the rate of increase in the inflow of air to a desiredvalue. Were this baflle not present, a maximum inflow of air would takeplace almost immediately upon the opening of the choke valve. Thecontinued upward movement of the plunger rod 21 is soon arrested by thechoke valve 18 contacting with the catch finger 56 of the catch 52.Catch finger 56 stops the upward movement of the choke valve, therebycausing the engine to operate under a partially choked cbndition. As theengine becomes warm, the thermostatic bellows expand and effect theopening of gate valve 50. As gate valve 50 commences to open, the catchfinger 56 is withdrawn from engagement with the choke valve, therebypermitting this valve to continue its upward movement and ending thechoking action thereof. Choke valve 18 and plunger 21 continue theirupward movement resulting from the suction in pneumatic cylinder 40until compression spring '34 in dash-pot 26 checks the same therebygradually bringing these members to rest. The removal of the choke valvefrom the vicinityof the bathe-22 and the opening of gate valve 50automatically ends the choking action of the choke valve.

Should the engine 1 for any reason tend to stall after the choke valveis partially or completely open, the suction in the pneumatic cylinder40 will fail and the choke valve and plunger rod will fall sufficientlyunder the action of spring 34 and gravity to check this tendency byincreasing the choking action of the automatic choke, resulting in aricher mixture and the continued operation and pick-upof the engine. Theupper surface of catch finger 56 is beveled so as not to prevent thefree downward movement of the choke valve. \Vhen the downwardly movingchoke valve strikes the beveled upper surface of the catch finger, thecatch 52 is forced outwardly opening the gate valve 50 slightly duringthe passing of the choke valve. After the passage of the choke valve,the gate valve closes under the action of gravity which closing actionmay be assisted by a spring, if desired.

It will be noted that the dash-pot 26 does not restrict the freedownward movement of the choke valve and plunger rod in accordance withpressure variations in cylinder 40, for during such downward movement,the relief valve 31 is open as shown in Fig. 4 permitting liquid to flowreadilythrough the apertures inrheck piston 28. In other words, when theautomatic choke of this invention is employed, the choking of the engineis varied automatically in accordance with the requirements thereof,thereby eliminating possible stalling and consequent restarting thereof.

In the event that the gate valve 50 is operated manually from the dashinstead of using the thermostatic bellows, it is merely necessary tooperate this valve after the engine at either of two positions by use ofthe recesses 53 and 54, the temporary partial open ing of the chokevalve, effected when recess 54 is used and while the engine is warmingup, can be "eliminated in warm weather, if desired, by using the recess53. The catch 52 may be eliminated altogether if desired, in which casethe automatic action of piston 37 and the choke valve 18 will sufiice toautomatically choke the engine. In such case it will be apparent thatwhen the engine starts, the choke valve will rise gradually under therestrictive action of the dash-pot until the valve is completely open.If the engine should tend to stall during the starting operation, thechoke valve will drop sufl'iciently to correct such tendency. In theevent that the catch 52 is not" employed, the gate valve 50 will stillserve the function .of relieving excess pressure developed-in the chokevalve casing such as that caused by back fir- 1n Inasmuch as the novelautomatic choke of this invention supplies just the amount of airnecessary for the most efficient operation of the engine, both atstarting and under continued' working conditions, it will be apparentthat the employement of the device of this invention eliminates floodedcarburetors and prevents waste of fuel and dilution of crank-case oil.

As many changes could be made in the above construction and manyapparently widely diflerent embodiments of this invention could be madeWithout departing from the scopethereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limitin sense.

Vl hat is claimed'is 1. In combination with a carburetor, choking meansfor regulating the supply of air to said carburetor, said choking meanscomprising asyalve automatically operated in response to variations, inthe Vacuum applied to said carburetor, and dash-pot means for retardingany decrease in the choking effect of said valve, but offeringsubstantially no resistance to an increase in the choking efiect.thereof.

2. In .combination with a carburetor, a choke comprising, a chokev'alve, a casing having an air lnlet opening controlled by said chokevalve and an air outlet opening connected to said carburetor, a plungerconnected in driving relation to said choke valve, a pneumatic cylindercommunicating with the vacuum applied to said corburetor, a pistonoperating in said pneumatic cylinder and connected to said plunger, saidpiston being actuated in accordance with the degree of vacuum applied tosaid carburetor for effecting the operation of said choke valve, a gatevalve connected to said casing and thermal means for effecting theopening of said gate valve valve.

3. In combination with a carburetor for an internal combustion engine, achoke comprising, a'choke valve, a casing having an air inlet openingcontrolled bysaid choke valve and an air outlet opening connected tosaid carburetor, a plunger carrying saiid choke valve, a pneumaticcylinder communicating with thevacuum applied to said carburetor, apiston operable in said pneumatic cylinder and connected to said plungerfor effecting the operation of said choke valve in accordance with \thedegree of vacuum applied to to thereby by-passsaid choke saidcarburetor, a gate valve mounted on said casing for closing an openingadapted to by pass said choke valve, and a catch carried by said gatevalve and adapted to r%trict the opening of said choke valve.

4. In combination with a carburetor for an internal combustion engine, achoke comprising, a choke valve, a casing having an air inlet openingcontrolled by said choke valve and an air outlet opening connected tosaid carburetor, a plunger carrying said choke valve, a pneumaticcylinder communicating with the vacuum applied to said carburetor,

a piston operable in said pneumatic cylinder and connected to saidplunger for effecting the operation of said choke valve in accordancewith the degree of vacuum applied to .said carburetor, a gate valvemounted on said casing for closing an opening adapted to by-pass saidchoke valve, and a catch carried by said gate valve and adapted torestrict the opening of said choke valve, and means for opening saidgatevalve to thereby remove said catch from operable connection withsaid choke valve so as to permit the full opening of the latter. a

5. In combination with a carburetor, a choke comprising, a choke valve,a casing having anair inlet opening controlled by said choke valve andan air outlet opening connected to said carburetor, and pneumatic meansconnected with said-choke valve and actuated in accordance with thedegree of vacuum applied to said carburetor for effecting the operationof said choke valve and a liquid dash-pot connected to said choke valvefor retarding the opening movement of

